Lack of Wake Vortex at WTC = No Planes?

reply to post by ipsedixit


Good find on that diagram. It's one of the tols we use to teach pilots about vortices, a picture is worth a thousand words.

Now, to clarify for everyone, what that is depicting is the behaviour of the vortices, after they leave the wingtips (or, more correctly, after the airplane leaves!!).

They have no real movement ALONG their axis of rotation. The diagram shows how, when generated near the ground, they will drift HORIZONTALLY, at about 3-5 kts, depending on the airplane, in a NO WIND condition (calm winds). They also tend to sink, slightly, after formation. An airplane in cruise flight, at a higher altitude, they will sink down about a couple of hundred feet below where they were formed, and depending on the air's stability, will persist for several minutes, slowly losing energy and disipating.

The diagram is a visual aid to help illustrate how an airplane on a parrallel runway to yours can be a hazard, from the vortices --- because they will spread, AND they will also be carried with any crosswind as well, SO if you're on a parallel runway and you are DOWNWIND of a large airplane, you should be cognizant of that possibility.

In NYC, that day, the winds were not real strong, at about 1,000 feet, but you can see obvious wind by looking at the smoke patterns. The vortices left by the airplanes would, as always, form, tend to sink downward, and horizontally with the prevailing breeze. Fire mostly tends to rise, and the smoke with it, initially at least.

Again, also, recall the forces of the explosive gasses, they will have more momentum than the relatively puny vortices.

Originally posted by weedwhacker
They have no real movement ALONG their axis of rotation.

You are leaving wiggle room there. Keep in mind that the vortices we are talking about are strong enough to induce roll in a following airplane if it gets to close to them. They can even impact the structural integrity of a following aircraft, depending on the exact aircraft and circumstances.

These vortices are not insignificant and are related to the weight of the aircraft that creates them. Stronger vortices being produced by heavier aircraft.

I still think that people who bring this issue up are not merely blowing smoke as some would have us believe.

Originally posted by ipsedixit


Keep in mind that the vortices we are talking about are strong enough to induce roll in a following airplane if it gets to close to them. They can even impact the structural integrity of a following aircraft, depending on the exact aircraft and circumstances.

Of course, that is true. Again, though, it is the ROTATION along an axis that you are referring to. In the 'clean' configuration, at a higher speed, they are somewhat less strong than when the airplane is heavy, slow and 'dirty'.

These vortices are not insignificant and are related to the weight of the aircraft that creates them. Stronger vortices being produced by heavier aircraft.

True again, see above.

I still think that people who bring this issue up are not merely blowing smoke as some would have us believe.

Well...did you not read the other parts of my post?

AS TO their strength, I can relate personal experience. Very occasionally, in a large jet, we will encounter the vortices (or one vortex) from someone ahead. It imparts a fairly sudden roll moment, but is easily countered with aileron. Sometimes, if we cross at an oblique angle, it is just a sharp, sudden bump. To passengers, it is usually indistinguishable from other types of turbulence.

A smaller airplane (lighter weight) will roll more, but not any more rapidly. Wake turbulence encouters are quite brief, and transient. They are DANGEROUS near the ground, for the reasons already noted (heavy, 'dirty'...) and that recovery may not occur in time before impacting the ground.

Back to NYC: Note the prevailing winds, when you look at the videos of the burinig buildings. Try to visualize the vortices, now that you've learned more about them.

I have an open mind to the NPT, but I'm not yet convinced.

The problem with comparing WTC 9/11 plane #2 and all those other videos of planes and test smoke is aircraft speed.

Notice how those planes in the test/demonstration videos are traveling near landing approach speed (~150 knots or so)? The 9/11 planes are traveling around 450 to 500 knots.

What that means is that the vortex doesn't show up at the same distance from the aircraft. When the 9/11 planes hit the building and stop creating vortex, it disrupts the generation of the vortex at that location and somewhat aft (remember the speed issue). And whose to say that a big building wouldn't block the intake of air a vortex needs to propagate? The dynamics of air near the building (several hundred feet at least) would have to have some sort of effect on the vortex's ability to grow.

Additionally, what does anyone here know about the effects of huge thermal explosions are on vortexes of planes that collide with buildings at over 450 knots? I suspect there are very few people on the planet, if any, that have studied that scenario.

What I'm saying is you are comparing apples to oranges. Different speeds, different thermodynamic conditions, different air conditions, etc.

Interesting, but seriously lacking base line information.




[edit on 13-8-2009 by harrytuttle]

Originally posted by weedwhacker
Well...did you not read the other parts of my post?

Please be assured, when I'm involved in this sort of discussion and someone is responding to something I posted I do read their whole post. If I don't get something it won't be because I didn't read it.

I still think there is an issue here with aircraft produced turbulence. Some people have said that there is evidence of aircraft produced turbulence in the smoke above the impact area at the South Tower. But we don't see it below the impact zone, where there should be even more chance of it occuring.

If it doen't exist below the impact zone then it probably doesn't exist above it either considering as you pointed out, that the vortices tend to descend and move away from the line of flight.

Either the vortices should be evident from smoke movement at the impact site or they should not. I still haven't heard expert testimony on that point.

My hunch is that we should see evidence of them, particularly below the impact zone.

[edit on 13-8-2009 by ipsedixit]

In this aircraft wake simulation from a NASA website one can see the downwash clearly between the two vortices and also that there might be some forward momentum of the smoke used in the test as the plane passes through it. (A side view would really be required to state that with certainty.) That to me would indicate that an airplane's wake does indeed "follow" it to some extent.

oea.larc.nasa.gov...

[atsimg]http://files.abovetopsecret.com/images/member/c7b38ad7a415.jpg[/atsimg]

Edit: If you take the point between figures 1 and 2 as the point when the plane entered the building, wouldn't it be reasonable to expect to then see two vortices of smoke curling down the face of the building to the bottom after impact?


[edit on 14-8-2009 by ipsedixit]

The REAL funny thing, is that the big boss took the thread about John Lear/NPT down, and stuffed it into the hoax catagory.

Where they belong.

TWINCPONE

If you frequent infowars you'll understand.

reply to post by ipsedixit

Edit: If you take the point between figures 1 and 2 as the point when the plane entered the building, wouldn't it be reasonable to expect to then see two vortices of smoke curling down the face of the building to the bottom after impact?

I see exactly what you're alleging here, but the point is in those NASA photos ( a model in, BTW...calm air ) the smoke is there BEFORE the model "flies" through it!

What many of us are trying to say is that, irrespective of any disturbances in the air that existed from the airplane's passage, just milliseconds later the forces of the explosion and resulting expanding gasses would have overwhelmed the vortices.

Try an actual real-world every day comparison: An extremely gusty and windy day. Wingtip vortices will try to form, but the air will be too turbulent for cohesion. Vortices need calmer air to be stable, and to persist.

Capice?
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edit, typos, typos!! My Kingdom for better fingers!!!

And, since I'm editing anyway, notice in the NASA photos the smoke really doesn't move 'forward' with the model's motion. Neither does the air. The air DOES displace downwards slightly, but it is minimal, as seen.
That would be a result from the Coanda Effect.

[edit on 14 August 2009 by weedwhacker]

Originally posted by weedwhacker
I see exactly what you're alleging here, but the point is in those NASA photos ( a model in, BTW...calm air ) the smoke is there BEFORE the model "flies" through it!

The main vortices that form under the wings might have avoided the smoke from the impact but I think there is a chance that the secondary vortices that flow around the wingtips and then inward toward the space vacated by the moving fuselage of the plane would have encountered the smoke in the area below the impact zone and then shown up as two curls of smoke descending down the front of the building.

Instead what we see is light grey smoke hanging in the air under the impact zone. There really was very little wind that day, although obviously there was some. The smoke drifted . . . very slowly.

What many of us are trying to say is that, irrespective of any disturbances in the air that existed from the airplane's passage, just milliseconds later the forces of the explosion and resulting expanding gasses would have overwhelmed the vortices.

In the government's version of the event there is no explosion per se.

All the damage is done by the impact of the plane. Fuel ignites also and there is a fireball, but no explosion. (Some people have made screwy claims about the fuel ignition having an explosive effect akin to a fuel/air bomb. You're not one of them, are you? If so we really don't see eye to eye.)

But again, below the impact zone, there is little evidence of any turbulence except for immediately as the plane breeches the building.

In the NASA photos shown on page two of the thread there is a length of time before the secondary vortices form and start to descend. I know it is a very short time, but still one could think of it as a pause during which time smoke would have entered the zone soon to be occupied by these secondary vortices.

Try an actual real-world every day comparison: An extremely gusty and windy day. Wingtip vortices will try to form, but the air will be too turbulent for cohesion. Vortices need calmer air to be stable, and to persist.

The air was very calm and stable on 9/11, so the only real world cause of turbulence other than vortex turbulence caused by the airplanes would be thermal expansion of the fuel fire. Would that be enough to overwhelm the effects of the airplane-caused vortices? I don't know. But in any event, that sort of turbulence would be in effect mostly above the impact zone. Heat rises.

Below the impact zone, there is little evidence of turbulence and that is the problem.

And, since I'm editing anyway, notice in the NASA photos the smoke really doesn't move 'forward' with the model's motion. Neither does the air.

I agree with you here, but I would still like to see a side view of the wake simulation test. Even a slight forward motion of those vortices would be significant and possibly noticeable in our scenario.

The air DOES displace downwards slightly, but it is minimal, as seen.

This I don't agree with and I think the photos show clearly that the downward displacement is significant.

reply to post by ipsedixit


I see that I write too much, and you tend to misunderstand me, because I'm not clear and concise enough.

In the government's version of the event there is no explosion per se.

All the damage is done by the impact of the plane. Fuel ignites also and there is a fireball, but no explosion.

I don't wish to bog down in the semantics, as I'm not fully sure what the difference is...except that I would assume a thermal ignition and rapidly expanding hot gasses would resemble an explosion, in appearance, if not in forces. THAT was my point.

In the NASA photos shown on page two of the thread there is a length of time before the secondary vortices form and start to descend. I know it is a very short time ...

Yes, glad you agree. The fireball, and the smoke accompanying it, was very energetic --- that is why I used the gusty, windy, turbulent day as an example, NOT to suggest the conditions in NYC were such. It was the localized effects of the fireball, and the thermal heating forces, that would prevent the vortices from remaining coherent long enough to be sen in the smoke.

Is that clearer?

Below the impact zone, there is little evidence of turbulence and that is the problem.

Not really, whilst true that heat rises, ALL of the air in the immediate vicinity was disrupted, and unstabilized, even down below within several meters. One would think.....

The expanding fireball had to PUSH air ahead of it, so we don't see the invisible air "wave front". I'd think it would create quite a breeze.....

Originally posted by weedwhacker
The fireball, and the smoke accompanying it, was very energetic

It certainly appeared to be. Personally I don't think that what we saw was simply the result of a fuel fire igniting. I think there were explosives of some sort involved. However for the government's purposes it was important that this fact not be too obvious.

--- that is why I used the gusty, windy, turbulent day as an example, NOT to suggest the conditions in NYC were such. It was the localized effects of the fireball, and the thermal heating forces, that would prevent the vortices from remaining coherent long enough to be sen in the smoke.

I'm wondering about that you know. These vortices are not inconsiderable. On a nice day like 9/11 the Visual Flight Rules (they have been adjusted back and forth over the years) require that an airplane following a 757 on an landing approach path stay back 4 nautical miles, I believe. (For those who really want to get into the details about such things, look at the NASA webpage linked to earlier in the thread.)

You are the pilot. Do they allow you to tailgate a 757 on landing approach on gusty days?

(ipsedixit quoted by weedwhacker)

Below the impact zone, there is little evidence of turbulence and that is the problem.

Not really, whilst true that heat rises, ALL of the air in the immediate vicinity was disrupted, and unstabilized, even down below within several meters. One would think.....

The expanding fireball had to PUSH air ahead of it, so we don't see the invisible air "wave front". I'd think it would create quite a breeze.....

This air wave front as you call it would diminish in strength according to the inverse squares rule the further out it expanded from the building. Keep in mind that below the impact zone dust and debris spread out maybe fifty feet or so from the face of the building at which point it completely lost expansive energy.

My own view is that this dust, etc., should have encountered vortices which had scarcely diminished at all and that we should see some evidence of this, which we do not.

It's hard to be precise about all this and to draw definite conclusions. I'm simply saying that not to see some evidence of the effect of vortices produced by the airplane makes me suspicious.

There are numerous other reasons to be suspicious of videos shot of the South Tower impact. We don't have to go into all that here. And as I have said, I am not a no-planer. I just think that there is reasonable reason to believe that the video of this event is suspect (and that's putting it mildly).

There is no slam dunk here, just a lot of suspicious anomalies, that might be explainable, but which remain unexplained.

Your explanation of why we don't see evidence of the vortices might be right on, but I am unconvinced.

This is an exaggerated example but here is what one of those vortices can do:

oea.larc.nasa.gov...

After USAir Flight 427 (a Boeing 737) plunged from the sky near Pittsburgh on September 8, 1994, killing 127 passengers and 5 crew members, the NTSB frantically accelerated its efforts to determine what might have triggered the 6,000-ft nose dive. A bump (a sudden airspeed increase detected by the plane’s flight-data recorder) indicated that the 737 had encountered wake turbulence created by a Delta 727 that preceded Flight 427 into the Pittsburgh International Airport. Flight 427 trailed the 727 by 4.1 nmi, well within the FAA regulation that requires two planes of such weights to maintain a separation of 3 nmi. As part of the investigation to determine the potential impact of such an encounter, the NTSB requested that Langley conduct flights of its specially instrumented OV-10 and 737 research aircraft trailing an FAA 727 generating aircraft. Following the longest aviation accident investigation in safety board history (4 years), the results of this cooperative activity helped investigators conclude that the vortex encounter might have been the initiating mechanism resulting in a hardover failure of the rudder actuator, which was determined to be the primary cause of the accident.

reply to post by ipsedixit


I really doubt your assertion that there were explosives perfectly positioned and perfectly timed to explode exactly where the suicide pilots were going to hit the buildings, too many variables for that.

It is true that the B757, although not classed as a 'heavy', was found shortly after entering service to have a very strong wake, similar in intensity to larger, heavier jets, so for ATC purposes the "in-trail" separation standards in the terminal area are treated AS IF it were a 'heavy'. Five miles, with allowance to four.


Ah, then the tragic USAir B737, near PIT. There was also a similar event, a United B737 approaching Colorado Springs. Although Boeing doesn't manufacture the control surface actuators, they still had extreme liability should it be determined to be the culprit. (There are, naturally, muddy waters in this, both accidents, precisely because of Boeing's risk).

It's technical, but essentially it boils down to pilot technique in the wake turbulence encounters. (United involved Mountain Wave turbulence, but it was thought there was a defect in the actuator, causing a reverse hard-over. They have all been re-designed, of course.)

I hope you aren't trying to suggest that the B737 encounter with a B727 wake was sufficient to cause the crash?? Because, it's not. That was an aberration.


In any event, the attempted suggestion/inferrence that "NO PLANES" explains the perceived 'lack' of vortices is weak, and without merit, no matter how hard you try to spin it!

Originally posted by weedwhacker
I really doubt your assertion that there were explosives perfectly positioned and perfectly timed to explode exactly where the suicide pilots were going to hit the buildings, too many variables for that.

I think he may be referring to the "flash" just as the noses of both planes touched the buildings.

My hypothesis on this is that there may have been some sort of explosives in the noses of the planes to help open up the buildings and to ensure the full entrance of the planes into the buildings.

Originally posted by _BoneZ_

Originally posted by weedwhacker
I really doubt your assertion that there were explosives perfectly positioned and perfectly timed to explode exactly where the suicide pilots were going to hit the buildings, too many variables for that.

I think he may be referring to the "flash" just as the noses of both planes touched the buildings.

My hypothesis on this is that there may have been some sort of explosives in the noses of the planes to help open up the buildings and to ensure the full entrance of the planes into the buildings.

Agreed. A lof of people tried to argue for somekind of "static" explanation, but there are some serious counter answers.

Originally posted by _BoneZ_

My hypothesis ... may have been some sort of explosives in the noses of the planes ...

Oh dear, oh dear ...

Let me re-check your siggy....engineer???

Come on, BoneZ!!! NPT is bad enough, dn't give them more crackpot ideas!!!

Or, did I miss your -/sarcasm/- ON/OFF switch
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edit: Wait!! I know!! Atta got the idea from Bruce Willis, he had a shoulder-mounted bazooka and fired it just moments before impact!!

Yup, that's it. Equally plausible.

[edit on 14 August 2009 by weedwhacker]

reply to post by weedwhacker


I was actually hoping for a more professional opinion from you, weedwhacker, as you are an experienced pilot. Your post was a little below the belt and uncalled for. I realize it can be frustrating trying to have conversations with people who don't know what they're talking about, but you should know by now I'm not one of those.

Can I get an expert hypothesis from you as to what you think the flashes were from both aircraft when the noses touched the towers? And, mind you, the flash from the plane that the north tower was quite large. At least 3 or 4 floors if I remember correctly, which would've been over 30-40 feet. That's a rather large explosion for a fiberglass nose of a plane to accomplish.

Bonez brings up a good point.

I have read other variations on it. As I keep reiterating (with reason I think), I am not a no planer. Jumping from the quite reasonable assumption that video has been tampered with in some way or at the very least is very anomalous to the conclusion that no planes hit the towers is, I think, to put on one's "seven league boots" or, in other words, to go too far.

There are just a lot of unexplained oddities in the 9/11 story. Too many. Maybe weedwhacker is right. Maybe the vortices are a non issue. I'm still doubtful about it and I don't think that is an unreasonable position.

reply to post by _BoneZ_


Oh...sorry, I actually thought you were joking. My bad...

My impression has been that certain videos have been --- *ahem* --- "enhanced" with the 'flashes', since they don't seem to appear on all versions.

AS FAR AS what's onboard, in the nose? That's where the Radar antenna is mounted. The radome is a honeycomb epoxy composite, not just plain fibreglass. In cross/section the diameter of the forward pressure bulkhead, where the antenna is mounted, is just a few feet...I'd estimate between six-seven feet in diameter. There isn't a whole lot of space there.

I'm sure there are supporting photos somewhere...Arliners.net is a good source, for comparisons and perspective.

**edit) Found this: Radome open

The airplanes were real, they were normal. Some 'conspiracy' people point to the BTS data, saying that both American flights are "missing", and therefore nonexistent. FALSE. There is ample history of the flights in the record, as having been scheduled, even for several days after the Airspace System was shut down. They were in the system, status as 'cancelled', just like every other airline.

AAL was proactive that morning, to DELETE the ACARS OUT/OFF times for their flights (UAL did not, their data is still there). WHY would AAL do that? Probably either a standard procedure after a crash, or out of deference to the families. Could be how their system works, different than United's?


[edit on 14 August 2009 by weedwhacker]

Originally posted by weedwhacker
My impression has been that certain videos have been --- *ahem* --- "enhanced" with the 'flashes', since they don't seem to appear on all versions.

Nobody in the 9/11 truth movement has "enhanced" or otherwise altered any video.

Originally posted by weedwhacker
AS FAR AS what's onboard, in the nose? That's where the Radar antenna is mounted.

Yes, I know this.

Originally posted by weedwhacker
The airplanes were real, they were normal.

Yes they were real. As far as "normal", that's still debateable.


You still didn't give your professional opinion as to what caused the flashes. Are you saying that the flashes are from the radar equipment in the nose?